Leaf Epidermal Microscopy, Chemo-Microscopy and GC-MS Analyses of Three Ocimum Species from Nigeria

Abstract

Comparative analyses of the leaf epidermal microscopy, chemo-microscopy and GCMS analysis of essential oils from three Ocimum species were analyzed. Ocimum belong to the family Lamiaceae. Leaf epidermal microscopy revealed anomocytic stomata in the species studied. Ocimum basilicum has anomocytic stomata on both surfaces but were more abundant on the lower surface; cell walls were wavy on the upper surface and had glandular trichomes on both surfaces. Ocimum canum had anomocytic stomata on both surfaces; cell walls were wavy and trichomes were glandular and non-glandular occurring on both surfaces but occurring more on the upper surface. The non-glandular trichomes are cone-shaped with pointed tip. Ocimum gratissimum has anomacytic stomata on both surfaces occurring more on the lower surface; the cell walls are curved on both surfaces and glandular trichomes occur on both surfaces which are more abundant on the lower surface. The glandular trichomes are radially flagellated in all the species studied. Lignin, tannins, cellulose, mucilage, starch, calcium oxalate, oils and proteins were observed in all species studied. The GC-MS analyses of the leaf essential oils revealed 35 compounds for O. basilicum, 49 compounds for O. canum and 34 compounds for O. gratissimum with 3-allyl-6-methoxyphenol being the most abundant in O. basilicum (34.42%); 1-Cyclopentene-1-methanol,2-methyl-5-1-methyl, the most abundant in O. canum (29.56%) and thymol being the most abundant in O. gratissimum (48.04%). The leaf epidermal microscopy and the chemo-microscopy can be used for the standardization of the plant. Chemical composition of the three Ocimum species can be used for the treatment of several diseases.